Method and apparatus for firing oil stills



Feb. 4, 1936. c. H. THAYER METHOD AND APPARATUS FOR FIRING OIL STILLS Filed Aug. l5, 1935 EN QQBU \w. c Q.e f m A YP, H@ e l m Z. C

Patented Feb. 4, 1936 f 2,029,956

UNITED sTATEs PATENT oFFicE METHOD AND APPARATUS FOR FIRING OIL STILLS Clarence H. Thayer, Wallingford, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Application August 15, 1935, Serial No. 36,334 12 Claims. (Cl. 196--110) The present invention relates to an apparatus gaseous or liquid fuel is burned by burner I9, a and method for recovering and utilizing any limited quantity of air being admitted, if necesgases or vapors which escape or leak from the sary, through a controllable air inlet 20. The return bends or headers commoruy used in tubuflue gases from auxiliary Combustion chamber lar oil stills 0r heaters. I3 pass through duct ZI to cooler 22 and thence 5 In such stills the leakage from the return through branched duct 23 t0 the header bOXeS 4, bends .and other connections may at times be a thence through lorarlohed duet 24 to Combustion substantial amount of oil. This leakage not Zone B of the Stills. only represents a considerable loss, but also Air, for Supporting Combustion in Zone B of 1o creates a considerable nre hazard. It is apparthe Still, iS forced by fan 25 through cooler 22, i0 ent that if this leakage of oil can be recovered thence through duet 25 to air Dreheater I4, and and properly burned Within the Still, a proporthence through air duct 8 to the combustion tionate saving in the fuel cost can be effected Zone B of the Still.

and the fire hazard caused by this leakage can A more detailed deSCrptoIl of the operation be reduced 01' eliminated. of that part of the apparatus which comprises 15 It is therefore an object of the present inventhe present invention iS aS folloWS: tion to provide a method and apparatus for re- There iS Considerable leakage from return covering the vapors of any oil leaking from the bends 3, of the oil flOWrlg through the tubes l. return bends of oil stills and for utilizing the The 011 which leaks from return bends 3.1i it is same as part of the fuel for heating the still. hot already VaDorZed irl the tuloeS l, Will be iIl- 2O It is a further object of this invention to pro- Stahtly VapOrZed in header boXeS 4 aS a result vide a method and apparatus for recovering vthis of the relatiVely high temperatures eXiSthg there, leakage in a manner which will reduce to a miniand due to the fact that the pressure irl header mum the danger of re or explosion. boxes 4 is practically atmospheric. Since these other and further objects will be .apparent vapors are highly inflammable, they not only 25 to one skilled in the art on reading this speciconstitute an appreciable waste, but also create cation and on reference to the drawing attached a considerable fire hazard. In order to remove thereto and which forms a part thereof. l these vapors from the header boxes d, a portion Referring now to the drawing in which the 0f the flue gases in recirculation duct I3 are led single figure is a diagrammatic representation through duct I'I to auxiliary combustion cham- 30 of the apparatus for carrying out the present inber B8. In the operation of the tubular o'il stills vention: the relative amounts of fuel and air admitted A designates the heating zone of a tubular oil to the combustion zone of the still may be so still or heater having a series of tubes I arranged controlled that the flue gases issuing from the therein. The tubes I extend through the walls still may have a high enough free oxygen con- 35 of the heating zone A of the still and are content to support combustion. If so, it is necessary nected by return bends 3 in header boxes 4. Oil that the free oxygen content of the gases in duct to be heated is admitted to the tubes through I'I be reduced to a point where they will no longer pipe 5 and leaves the still through pipe 6. support combustion. This is accomplished by 40 B designates the combustion zone of the tububurning sucient fuel in chamber I8 by the burn- 40 lar oil still in which fuel from burner I is burned, er I9 to decrease the free oxygen content of the air to support combustion being introduced gases issuing from chamber I8, through duct 2|, through air duct 8. The hot gases from comto a point where they will no longer support combustion zone B rise through the 'heating zone A, bustion, if necessary a controlled quantity of air passing over the tubes I therein and heating the may be introduced into chamber I8 through the 45 oil flowing therein. These hot gases leave the controllable air inlet 2l). These gases then pass still through nues 9, a portion of them flowing through the cooler 2l where they are cooled by through flue Il), air preheater I4 and uel to indirect heat exchange with the air from fan vstack I6. The remainder of the gases from ilues 25. The cooled gases then` flow through branched 'o '50 9 are drawn down flue II by fan I2 and are flue 23 to theheader boxes 4. The cooled gases reintroduced to the combustion zone B of the flowing through the header boxes reduce the temstill through recirculation duct I3. perature of the return bends, particularly the `out- A portion of the gases from recirculation duct er portion such as the plug holding members, and I3 pass through duct I1, having Valve 33 therein, prevent distortion which might occur at high temto an auxiliary combustion chamber I8, in which peratures. In addition, since the gases from 55 branches duct 23 will not support combustion, the inflammable vapors of any oil leaking from the return bends 3 cannot ignite, but such inflammable vapors are mixed with the inert gases in header boxes 4, and this mixture of inert gases and iniiammable vapors leave the header boxes 4 through branched duct 24 to the combustion zone B of the still. Here the inflammable vapors from header boxes 4 will mix with the air introduced by air duct 8 and be burned, thus serving as part of the fuel for heating the oil flowing in tubes l.

Various modifications will occur to one skilled in the art. For instance, instead of taking flue gases from recirculation duct i3 and introducing them into auxiliary combustion chamber I8, flue gases may be drawn from iiue it through duct 27, having valve 3Q therein, by fan 28 and introduced into chamber i8, the valves 33 and 32 being closed. Or valves 33 and Si? may be closed and valve 32 in line 3i opened and flue gases may be taken from flue i5 through lines 3l and 2?, by fan 28, and introduced into chamber i3, since the gases in flue i5 are partially cooled after passing through air preheater I4, the cooler 22 may be omitted. Instead of using any of these sources for liuc gases to be introduced into chamber i8 and thence into header boxes 4, the combustion chamber I8 may be used as a iiue gas generator to supply ilue gases for introduction into header boxes 4, the amount of aii` admitted through controllable air openings 2! being so regulated that the flue gases issuing from chamber i8 will not support combustion. Or, if desired, steam or some. other inert gas may be admitted to the header boxes li and used for removing the vapors of any oil leakage therefrom, as by closing valves Sii, 32 and 33 and admitting the steam o'r other inert gas, through controlled inlet 2li to chamber lil and thence through ducts 2l and 23 to the header boxes d.

In case the oil leakage is greater than the fuel requirements of the oil still or heater, or when it is desired to shut 01T the res therein, as when shutting down, part or all of the inert gas and oil vapor mixture flowing through duct 24 may be vented through valved duct 29 to the atmosphere.

What I claim and desire to protect by Letters Patent is as follows:

l. The method for removing from the header boxes or" the tubular oil stills the vapors of oil escaping thereinto from the return bends of said stills, which comprises introducing an inert gas into the header boxes, and removing said inert gas with the oil vapors mixed therewith from said header boxes.

2. The method or" minimizing leakage of oil from the return bends of the tubes of an oil still into the header boxes enclosing said return bends which comprises ilowing through the header boxes an inert gas at a temperature substantially below the temperature in the combustion zone of the still.

3. The method of minimizing leakage of o'il from the return bends of the tubes of an oil still into the header boxes enclosing said return bends which comprises circulating a portion o'f the flue gases from said still through the header boxes.

4. The method for recovering vapors escaping from return bends of an oil heating still and utilizing the same for fuel, which comprises mixing said vapors with an inert gas and introducing said mixture into the combustion zone of said still.

5. Ihe method for recovering vapors escaping from the return bends of an oil heating still and utilizing the same for fuel which comprises circulating a portion of the flue gases from said still past said return bends and introducing the gases thus circulated into the combustion zone of said still.

6. The method for recovering vapors escaping from the return bends of an oil heating still, which comprises mixing a portion of the iiue gases from said still with an inert gas to form a non-combustion supporting mixture, passing said mixture around said return bends and then introducing said mixture into the combustion zone of said still.

'7. The method of recovering and utilizing the vapors of oil leaking from the return bends of oil heating stills which comprises withdrawing a portion of the flue gases from said still and burning suicient fuel in the gases thus withdrawn to lower the free oxygen content of the same to a point where said flue gases will no longer support combustion, then flowing said gases past said return bends and then introducing said gases into the combustion zone of said still.

8. The method of recovering and utilizing the vapors of oil leaking from the return bends of oil heating stills which comprises withdrawing a portion of the flue gases from said still, burning suiicient fuel in the gases thus withdrawn to lower the free oxygen content of the same to a point where said ue gases will no longer support combustion, cooling said gases, owing said gases past said return bend and then introducing said gases into the combustion zone of said still.

9. The combination with a tubular oil still in which the tubes are connected by return bends of header boxes surrounding said return bends, means for introducing an inert gas into said header boxes, and means for flowing gases from said header boxes to the combustion zone of said still.

10. The combination with a tubular oil still in which the tubes are connected by return bends of header boxes surrounding said return bends, means for withdrawing a portion of the flue gases from said still, means for burning a controlled quantity of fuel in the gases thus withdrawn,

means for introducing said gases to said header boxes, and means for flowing said gases from said header boxes to the combustion zone of said still.

1l. 'I'he combination with a tubular oil still in which the tubes are connected by return bends of header boxes surrounding said return bends, means for withdrawing a portion of the ue gases from said still, means for burning a controlled quantity of fuel in the gases thus withdrawn,

means for cooling said gases, means for introf1 ducing said gases to said header boxes, and means for flowing said gases from said header boxes to the combustion zone of said still.

12. The combination with a tubular oil still in which the tubes are connected by return bends of header boxes surrounding said return bends, means for generating non-combustion supporting flue gases, means for introducing said gases to said header boxes, and means for owing said gases from said header boxes to the combustion zone of said still.

CLARENCE H. THAYER. 

